1. Field of the Invention
This invention relates to a device for changing the needle boards of an apparatus for needling nonwoven webs, which apparatus comprises a plurality of vertically movable board carriers, which are arranged in a row extending in the direction of the working width of the apparatus and to which the needle boards are adapted to be detachably secured, and an assembling track, which extends along said row on both sides thereof and is adapted to support and guide the needle boards, which are adapted to be interconnected by tension-resisting coupling means, which device comprises a magazine for supporting a plurality of said needle boards in respective superposed slide tracks.
2. Description of the Prior Art
In needling apparatuses having a relatively large working width, a plurality of independently mounted board carriers are arranged in a row extending in the direction of the working width of the apparatus so that the loads imposed by the reciprocating motion of the board carriers can be taken up in an improved manner. In dependence on the pitch of the board carriers, a plurality of needle boards are provided, which are secured to the board carriers and during the needling operation the needles of the needle boards pierce at a predetermined stroke frequency the web, which is moved between a backing and a stripper. But that arrangement of the needle boards will render the replacement of the needle boards more difficult. Such a replacement will be required when needles have become worn or damaged or when the needle pitch is to be changed. After the needle boards have been detached from the board carriers, the needle boards must be taken up by assembling trucks, which have been pushed into the needling apparatus along an assembling track extending on both sides of the row of board carriers. Thereafter the assembling trucks interconnected by tension-resisting coupling means are extracted from the needling apparatus and after each extraction step the currently leading needle board is lifted by hand from the assembling truck and placed into a magazine which has been provided. Thereafter the now empty assembling truck is uncoupled from the next succeeding assembling truck and is removed. The assembling of new needle boards is effected by the same operations in a reverse sequence: A needle board is taken from the magazine, which has been provided with properly prepared needle boards, and that needle board is placed into an assembling truck, which is then pushed along the assembling track into the needling apparatus so that space is then available for another assembling truck, which is to be coupled and is to receive the next needle board. It is apparent that the needle boards are moved step by step into the needling apparatus until each needle board is disposed under the associated board carrier and can be secured thereto. When the new needle boards have been assembled, the board carriers are raised and the assembling trucks are then extracted from the needling apparatus and stored for use when the needle boards are to be changed again.